Papers by Author: Xue Ran Deng

Abstract: A simple solar-blind ultraviolet (UV) detector was fabricated by using Al0.3Zn0.7O alloy thin films as photocathode and ZnO:Al (AZO) thin film as transparent electrode. Transmission spectra of Al0.3Zn0.7O alloy thin film was characterized through spectrometer and result showed significant enlargement of its optical band gap value. This alloy film only absorbed illumination whose wavelength is below 280nm, and the UV on/off characteristics of this detector presented very clearly. Scanning electron microscope (SEM) image revealed fine structure of both layers and the interface of these two layers performed clear and uniform.

Abstract: The III-nitride compounds epitaxially grown on Si substrate have attracted more and more attentions and some progress have been achieved. Many methods have been tried to tackle the issue which caused by the large lattice mismatch and thermal expansion coefficient mismatches between silicon substrate and the III-nitride compounds. This paper presents buffer layer technology, selective area and lateral epitaxial over growth technology, and presents the researches about the III-nitride devices. Semi polar and non-polar GaN films grown on Si (such as Si(110), Si(112), Si(001) et al.) also have been instructed. At the end of this paper, the development trend of epitaxial technology has been discussed.

Abstract: Large area (13mm*13mm) PbS thin films with (200) preferred orientation were prepared by chemical deposition. The optical properties of PbS films with annealing treatment in various forming gases with different ratio of nitrogen-oxygen (100ml/min of N₂&O₂(3:1), 100ml/min of N₂&O₂(2:1), 100ml/min of N₂&O₂(1:1), 50ml/min of O₂) were deeply analyzed. X-ray diffraction (XRD), scanning electron microscope (SEM), high and low temperature test chamber and other test methods for photosensitivity were used to investigate the structure and photoelectric properties of PbS films. The results showed that with proper amount of oxidation (when nitrogen-oxygen ratio was 1:1), the impurity barrier tended to fully grow, impurity activation energy increased to 0.314eV, dark resistance reached up to 30.2MΩ, and the photoconductive sensitivity of PbS thin film under this process was about 4 times larger compared with air annealing. According to the analysis of XRD patterns and surface morphologies of films, it can be seen that nitrogen in this process was not only to prevent PbS thin films from excessive oxidation, but also inhibited the formation of surface defects and enhanced the stability of PbS device.